Researchers at Liverpool John Moores University explored how unconscious associations between scent and color influence color perception. The study appeared in the scientific journal Frontiers in Psychology (FIP).
The experiment involved 24 adults ranging from 20 to 57 years of age. Participants entered a room carefully prepared to minimize extraneous sensory input. Five distinct scents were introduced in rotation: caramel, cherry, lemon, mint, and coffee, with plain water serving as a baseline control.
Following each sniff, participants adjusted the color of a square displayed on a screen, dialing it toward a neutral gray using two sliders to indicate the perceived gray tone.
Findings revealed that odors biased color judgments away from true gray. For instance, coffee odor tended to push the square toward red-brown hues, caramel favored yellowish tones, cherry nudged colors toward pink, red, and purple, while lemon shifted toward yellow, green, and pink combinations.
Interestingly, even the neutral water scent produced fewer gray adjustments, whereas simply smelling mint influenced gray perception as well.
Dr. Ryan Ward, the lead author, explained that the results demonstrate cross-modal associations for four of the five scents tested, specifically lemon, caramel, cherry, and coffee, in shaping gray perception.
Earlier work in the field has suggested that emotional perception can be affected by the color context associated with a person’s facial expression, indicating a broader link between sensory modalities and social perception. This study adds to that growing body of knowledge by showing how olfactory cues can subtly alter visual judgments in common tasks.